A railway vehicle and the like include sliding doors. Such a sliding door is suspended by a door suspension device (for example, refer to WO2012/157492). The door is driven to open or close by an opening/closing drive mechanism which uses air pressure or an output of an electric motor.
The door suspension device described in WO2012/157492 includes a first door roller which travels on a lower rail among an upper rail and the lower rail that are parallel to each other, a first door roller supporting member which suspends a door and which rotatably supports the first door roller, and swinging members coupled to the first door roller supporting member.
In addition, the door suspension device includes a second door roller which is supported by the swinging members and which is capable of coming into contact with the upper rail and a drive coupling section for holding and coupling the door with respect to the opening/closing drive mechanism. Furthermore, the door suspension device includes an elastic coupling mechanism which couples the swinging members and the drive coupling section to each other. The elastic coupling mechanism includes an elastic section capable of changing relative positions of the second door roller and the drive coupling section by elastically deforming.
The swinging members are respectively arranged on a door head side and a door tail side of the door and are coupled to two second door rollers. The door head-side swinging member is coupled to a swinging coupling member arranged on the door head side. In addition, the door tail-side swinging member is coupled to a swinging coupling member arranged on the door tail side. The respective swinging coupling members are linking members and are penetrated by a bolt referred to as a coupling shaft member in a state where the swinging coupling members are lined up in an opening/closing direction.
A tip of the bolt is fixed to the drive coupling section by screw joining. A coil spring is fitted to the bolt and is arranged between a head of the bolt and the door head-side swinging member.
Three nuts are fitted to the bolt. Specifically, a bolt (41) is fixed to a coupling member (35) of a drive coupling section (28) by a lock nut (42a). In addition, two nuts for positioning the bolt with respect to each of two swinging coupling members (31 and 32) are provided.
According to the configuration described above, a distance between the two swinging coupling members changes due to an elastic deformation of the elastic section and, as a result, each swinging member swings. Accordingly, the second door rollers coupled to the respective swinging members are displaced in a direction approaching or receding from the upper rail. As a result, during acceleration or deceleration when the door is being driven to open or close, due to the displacement of the swinging members with respect to the door caused by the elastic deformation of the elastic section, each second door roller is displaced in a direction approaching the upper rail. Accordingly, a load (surface pressure) acting on the upper rail from the second door rollers temporarily increases.
Subsequently, when the door starts moving at a uniform speed, the elastic section immediately returns to its original shape and a distance relationship between the upper rail and the second door rollers is restored to its original state. As a result, by installing the second door rollers so that the second door rollers come into contact with the upper rail relatively slightly, travel resistance is reduced with respect to a mechanism that prevents derailment when the door rollers travel on the rail. In addition, during acceleration and deceleration of the door and the like, the second door rollers are positioned at appropriate positions and derailment of the door rollers and tilting of the door are prevented.
As described above, the bolt to which the coil spring is attached requires three nuts. Due to this configuration, a position adjustment operation of the bolt (41) with respect to three members, namely, the swinging coupling members (31 and 32) and the coupling member (35) must be performed. As a result, a configuration of the elastic coupling mechanism (29) including the bolt (41) becomes complicated.